Getfeatureinfo

Definition

GetFeatureInfo is a request method used in Web Map Services (WMS) to retrieve information about a specific geographic feature that is displayed on a map. When a user clicks on a feature, this method sends a query to the server, which responds with attribute data related to the clicked feature, such as its name, type, or any other associated data. This interaction allows users to gain detailed insights about the features on the map without having to view an entirely separate dataset.

5 Must Know Facts For Your Next Test

1. The getfeatureinfo request typically returns data in formats like XML or JSON, making it easier for applications to parse and display information.
2. This method is essential for enhancing user interactivity with maps, as it allows for dynamic querying of spatial data.
3. GetFeatureInfo requests often include parameters such as 'layer', 'query_layers', and 'info_format', which specify what data to retrieve.
4. It helps bridge the gap between visual representation and underlying data by providing context for what users see on the map.
5. Implementing getfeatureinfo effectively can significantly improve user experience by enabling quick access to relevant feature information.

Review Questions

• How does the getfeatureinfo method enhance user interaction with web maps?
  • The getfeatureinfo method enhances user interaction by allowing users to click on specific features within a web map and instantly receive detailed information about them. This interactivity transforms static maps into dynamic tools where users can explore and obtain insights into geographic data without navigating away from the map itself. By enabling real-time queries, users can access relevant attributes of features, making their experience more engaging and informative.
• In what ways do the parameters included in a getfeatureinfo request affect the output received from the server?
  • The parameters in a getfeatureinfo request significantly influence the output by determining which features are queried and how the results are formatted. For instance, specifying 'layer' identifies which map layer to query, while 'query_layers' can define additional layers for context. The 'info_format' parameter dictates how the data is returned, whether in XML or JSON. Each of these parameters plays a crucial role in tailoring the response to meet specific user needs.
• Evaluate the importance of getfeatureinfo within the broader context of web-based geographic information systems (GIS).
  • GetFeatureInfo is vital within web-based GIS as it directly connects visualization and data retrieval, fostering a more interactive user experience. By facilitating instant access to feature-specific information, it empowers users to make informed decisions based on real-time data insights. As GIS applications become increasingly integral for spatial analysis and decision-making across various fields, the role of methods like getfeatureinfo becomes even more pronounced. Its integration into web mapping technologies ensures that users not only see but also understand the significance of the spatial data presented.

Related terms

Web Map Service (WMS): A standard protocol for serving georeferenced map images over the Internet, enabling users to request maps based on specified parameters.

Feature: A distinct object or element in a geographic dataset, such as a point, line, or polygon that represents real-world entities.

Coordinate Reference System (CRS): A system that uses coordinate values to represent geographic locations, ensuring that features are correctly positioned on the Earth's surface.